Fluorosurfactants which incorporate betaine groups are known for use as additives in fire extinguishing compositions. For example U.S. Pat. No. 6,521,730 discloses a fluorosurfactant having a betaine group represented by the formula (N+—CH2—CO2−). The betaine group allows such fluorosurfactants to undergo electrostatic interactions with other components in a fire fighting composition therefore improving performance.
U.S. Pat. No. 6,518,345 which discloses a fire fighting composition comprising a betaine containing fluorosurfactant, a polyethyleneimine, and a polybasic acid. The polybasic acid is necessary for the purpose of undergoing electrostatic interactions with the polyethyleneimine thereby improving the flame resistance and fuel resistance of the composition. Apparently, the fluorosurfactant alone could not sufficiently undergo electrostatic interaction with the polyethyleneimine to improve the flame resistance and fuel resistance.
It would be desirable to discover a fluorosurfactant having an increased ability to undergo electrostatic interaction with other components of a fire fighting composition thereby improving the performance of the fire fighting composition.